TERC promotes cellular inflammatory response independent of telomerase

TERC promotes non-small cell lung cancer progression by facilitating the nuclear localization of TERT

The core of telomerase consists of the protein subunit telomerase reverse transcriptase (TERT) and the telomerase RNA component (TERC). So far, the role of TERC in cancer development has remained elusive. Here, we found TERC expression elevated in non-small cell lung cancer (NSCLC) tissues, which was associated with disease progression and poor prognosis in patients. Using NSCLC cell lines and xenograft models, we showed that knockdown of TERC caused cell cycle arrest, and inhibition of cell proliferation and migration. Mechanistically, TERC was exported to the cytoplasm by nuclear RNA export factor 1 (NXF1), where it mediated the interaction of TERT with other telomerase subunits. Depletion of TERC hindered the assembly and subsequent nuclear localization of the telomerase complex, preventing TERT from functioning in telomere maintenance and transcription regulation. Our findings suggest that TERC is a potential biomarker for NSCLC diagnosis and prognosis and can be a target for NSCLC treatment.

Novel biomarkers identified by weighted gene co-expression network analysis for atherosclerosis

BACKGROUND

This study aimed to screen out the potential diagnostic biomarkers for atherosclerosis (AS).

METHODS

We downloaded the gene expression profiles GSE66360, GSE28829, GSE41571, GSE71226, and GSE100927 from the Gene Expression Omnibus (GEO) database. The differentially expressed genes (DEGs) were identified using the "limma" package in R. Weighted gene co-expression network analysis (WGCNA) was applied to reveal the correlation between genes in different samples. Subsequently, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed. The interaction pairs of proteins were retained by the STRING database, and the protein-protein interaction (PPI) network was visualized with the hub genes. Finally, the R packages "ggpubr" and "preprocessCore" were used to analyze immune cell infiltration.

RESULTS

In total, 40 overlapping genes both in GSE66360 and GSE28829 were found to be related to the occurrence of AS. Further, the top 10 network hub genes including TYROBP, CSF1R, TLR2, CD14, CCL4, FCER1G, CD163, TREM1, PLEK, and C5AR1 were identified as significant key genes. Moreover, four genes (TYROBP, CSF1R, FCGR1B, and CD14) were verified that could efficiently diagnose AS. Finally, the gene TYROBP was found to have a strong correlation with immune-infiltrating cells.

CONCLUSION

Our study identified four genes (TYROBP, CSF1R, FCGR1B, and CD14) that may be effective biomarkers for AS, with the potential to guide the clinical diagnosis of AS.

Association of Obesity with Telomere Length in Human Sperm

Background: Telomere attrition and mitochondrial dysfunction are two fundamental aspects of aging. Calorie restriction (CR) is the best strategy to postpone aging since it can enhance telomere attrition, boost antioxidant capacity, and lower the generation of reactive oxygen species (ROS). Since ROS is produced by mitochondria and can readily travel to cell nuclei, it is thought to be a crucial molecule for information transfer between mitochondria and cell nuclei. Important variables that affect the quality and functionality of sperm and may affect male reproductive health and fertility include telomere length, mitochondrial content, and the ratio of mitochondrial DNA (mtDNA) to nuclear DNA (nDNA). Telomere damage results from mitochondrial failure, whereas nuclear DNA remains unaffected. This research aims to investigate potential associations between these three variables and how they might relate to body mass index. Methods: Data were collected from 82 men who underwent IVF/ICSI at the University Hospital of Ioannina's IVF Unit in the Obstetrics and Gynecology Department. Evaluations included sperm morphology, sperm count, sperm motility, and participant history. To address this, male participants who were categorized into three body mass index (ΒΜΙ) groups-normal, overweight, and obese-had their sperm samples tested. Results: For both the normal and overweight groups, our results show a negative connection between relative telomere length and ΒΜI. As an illustration of a potential connection between mitochondrial health and telomere maintenance, a positive correlation was found for the obese group. Only the obese group's results were statistically significant (p < 0.05). More evidence that longer telomeres are associated with lower mitochondrial content can be found in the negative connection between telomere length and mitochondrial content in both the normal and overweight groups. However, the obese group showed a positive association. The data did not reach statistical significance for any of the three groups. These associations may affect sperm quality since telomere length and mitochondrial concentration are indicators of cellular integrity and health. Moreover, the ratio of mtDNA to nDNA was positively correlated with the relative telomere lengths of the obese group, but negatively correlated with the normal and overweight groups. In every group that was studied, the results were not statistically significant. According to this, male fertility may be negatively impacted by an imbalance in the copy number of the mitochondrial genome compared to the nuclear DNA in sperm. Conclusions: Essentially, the goal of our work is to determine whether mitochondria and telomere length in human sperm interact. Understanding these connections may aid in the explanation of some male infertility causes and possibly contribute to the creation of new treatment modalities for problems pertaining to reproductive health. The functional implications of these connections and their applications in therapeutic settings require further investigation.

Evidence of zoonotic pathogens through biophysically induced genomic variance

Zoonoses are infectious agents that are transmissible between animals and humans. Up to 60% of known infectious diseases and 75% of emergent diseases are zoonotic. Genomic variation between homeostatic populations provides a novel window into the effect of environmental pathogens on allelic distributions within the populations. Genodynamics is a biophysical approach utilizing developed metrics on biallelic single-nucleotide polymorphisms (SNPs) that can be used to quantify the adaptive influences due to pathogens. A genomic free energy that is minimized when overall population health is optimized describes the influence of environmental agents upon genomic variation. A double-blind exploration of over 100 thousand SNPs searching for smooth functional dependencies upon four zoonotic pathogens carried by four possible hosts amidst populations that live in their ancestral environments has been conducted. Exemplars that infectious agents can have significant adaptive influence on human populations are presented. One discussed SNP is likely associated with both adaptive and innate immune regulation. The adaptive response of another SNP suggests an intriguing connection between zoonoses and human cancers. The adaptive forces of the presented pathogens upon the human genome have been quantified.

Identification of polymorphic alleles in TERC and TERT gene reprogramming the telomeres of newborn and legacy with parental health

Telomere and telomerase genes (TERC and TERT) highlighted many novel genetic polymorphisms related to common diseases. This study explored the polymorphic alleles of TERC and TERT gene in parents-newborn (triad) and its association with telomere length (TL) and parental diseases (mother: Gestational Diabetes Mellitus (GDM), Preeclampsia, fathers: Diabetes, Hypertension). In this cross-sectional study, the blood samples (n = 612) were collected from parents-newborn triad (204 each) for TL (T/S ratio) quantification by using qPCR, and gene (TERC and TERT) polymorphism was detected by Sanger sequencing. The correlation analysis was used to find an association between paternal TL (T/S ratio) and newborn TL. The multivariate linear regression was applied to determine the effect of parents genes and diseases on newborn TL. A positive association (r = 0.42,0.39) (p < 0.0001) among parents and newborn TL was observed. In the diseased group, both TERC (rs10936599) and TERT (rs2736100) genes had a high frequency of allele C in newborns (OR = 0.94, P = 0.90, OR = 4.24, P = 0.012). However, among parents, TERT gene [Mother CC (B = 0.575; P = 0.196), Father CC (B = -0.739; P = 0.071)] was found significant contributing factor for Newborn TL. Diseased parents with T/T and A/C genotypes had longer newborn TL (2.82 ± 2.43, p < 0.022; 1.80 ± 1.20, p < 0.00) than the C/C genotype. Therefore, the study, confirmed that major allele C of TERC and TERT genes is associated with smaller TL in diseased parents-newborns of the targeted population.

Association of HOTAIR, MIR155HG, TERC, miR-155, -196a2, and -146a Genes Polymorphisms with Papillary Thyroid Cancer Susceptibility and Prognosis

Polymorphisms in long non-coding RNA and microRNA genes may play a significant role in the susceptibility and progression of papillary thyroid carcinoma (PTC). The current study investigates the polymorphisms HOTAIR rs920778, MIR155HG rs1893650, TERC rs10936599, miR-155 rs767649, miR-196a2 rs11614913 and miR-146a rs2910164 in 102 PTC patients and 106 age- and sex-matched controls of the Caucasian Serbian population, using real-time PCR. We observed differences in genotype distributions of the HOTAIR rs920778 (p = 0.016) and MIR155HG rs1893650 (p = 0.0002) polymorphisms between PTC patients and controls. HOTAIR rs920778 was associated with increased PTC susceptibility (adjusted OR = 1.497, p = 0.021), with the TT variant genotype increasing the risk compared to the CC genotype (OR = 2.466, p = 0.012) and C allele carriers (CC + CT) (OR = 1.585, p = 0.006). The HOTAIR rs920778 TT genotype was associated with lymph node metastasis (p = 0.022), tumor recurrence (p = 0.016), and progression-free survival (p = 0.010) compared to C allele carriers. Multivariate Cox regression revealed that ATA risk (HR = 14.210, p = 0.000004) and HOTAIR rs920778 (HR = 2.811, p = 0.010) emerged as independent prognostic factors in PTC. A novel polymorphism, MIR155HG rs1893650, was negatively correlated with susceptibility to PTC, with TC heterozygotes exerting a protective effect (OR = 0.268, p = 0.0001). These results suggest that the polymorphisms HOTAIR rs920778 and MIR155HG rs1893650 could be potential prognostic and risk biomarkers in papillary thyroid carcinomas.

Telomerase and hallmarks of cancer: An intricate interplay governing cancer cell evolution

Transformed cells must acquire specific characteristics to be malignant. Weinberg and Hanahan characterize these characteristics as cancer hallmarks. Though these features are independently driven, substantial signaling crosstalk in transformed cells efficiently promotes these feature acquisitions. Telomerase is an enzyme complex that maintains telomere length. However, its main component, Telomere reverse transcriptase (TERT), has been found to interact with various signaling molecules like cMYC, NF-kB, BRG1 and cooperate in transcription and metabolic reprogramming, acting as a strong proponent of malignant features such as cell death resistance, sustained proliferation, angiogenesis activation, and metastasis, among others. It allows cells to avoid replicative senescence and achieve endless replicative potential. This review summarizes both the canonical and noncanonical functions of TERT and discusses how they promote cancer hallmarks. Understanding the role of Telomerase in promoting cancer hallmarks provides vital insight into the underlying mechanism of cancer genesis and progression and telomerase intervention as a possible therapeutic target for cancer treatment. More investigation into the precise molecular mechanisms of telomerase-mediated impacts on cancer hallmarks will contribute to developing more focused and customized cancer treatment methods.

The Influence of TEP1 and TERC Genetic Variants on the Susceptibility to Multiple Sclerosis

Multiple sclerosis (MS) is a chronic inflammatory autoimmune disease of the central nervous system. According to recent studies, cellular senescence caused by telomere shortening may contribute to the development of MS.

AIM OF THE STUDY

Our aim was to determine the associations of TEP1 rs1760904, rs1713418, TERC rs12696304, rs35073794 gene polymorphisms with the occurrence of MS.

METHODS

The study included 200 patients with MS and 230 healthy controls. Genotyping of TEP1 rs1760904, rs1713418 and TERC rs12696304, rs35073794 was performed using RT-PCR. The obtained data were analysed using the program "IBM SPSS Statistics 29.0". Haplotype analysis was performed using the online program "SNPStats".

RESULTS

The TERC rs12696304 G allele of this SNP is associated with 1.4-fold lower odds of developing MS (p = 0.035). TERC rs35073794 is associated with approximately 2.4-fold reduced odds of MS occurrence in the codominant, dominant, overdominant, and additive models (p < 0.001; p < 0.001; p < 0.001; p < 0.001, respectively). Haplotype analysis shows that the rs1760904-G-rs1713418-A haplotype is statistically significantly associated with 1.75-fold increased odds of developing MS (p = 0.006). The rs12696304-C-rs35073794-A haplotype is statistically significantly associated with twofold decreased odds of developing MS (p = 0.008). In addition, the rs12696304-G-rs35073794-A haplotype was found to be statistically significantly associated with 5.3-fold decreased odds of developing MS (p < 0.001).

CONCLUSION

The current evidence may suggest a protective role of TERC SNP in the occurrence of MS, while TEP1 has the opposite effect.

Global Gene Expression of Post-Senescent Telomerase-Negative ter1Δ Strain of Ustilago maydis

We analyzed the global expression patterns of telomerase-negative mutants from haploid cells of Ustilago maydis to identify the gene network required for cell survival in the absence of telomerase. Mutations in either of the telomerase core subunits (trt1 and ter1) of the dimorphic fungus U. maydis cause deficiencies in teliospore formation. We report the global transcriptome analysis of two ter1Δ survivor strains of U. maydis, revealing the deregulation of telomerase-deleted responses (TDR) genes, such as DNA-damage response, stress response, cell cycle, subtelomeric, and proximal telomere genes. Other differentially expressed genes (DEGs) found in the ter1Δ survivor strains were related to pathogenic lifestyle factors, plant-pathogen crosstalk, iron uptake, meiosis, and melanin synthesis. The two ter1Δ survivors were phenotypically comparable, yet DEGs were identified when comparing these strains. Our findings suggest that teliospore formation in U. maydis is controlled by key pathogenic lifestyle and meiosis genes.

Dyskerin and telomerase RNA component are sex-differentially associated with outcomes and Sunitinib response in patients with clear cell renal cell carcinoma

BACKGROUND

Clear cell renal cell carcinoma (ccRCC) displays sex-biased incidence, outcomes, molecular alterations and treatment efficacy; however, clinical managements are largely identical in male and female patients. Moreover, many biomarkers have been identified as predictors for ccRCC outcomes and response to therapeutic drugs, such as multitargeted tyrosine-kinase receptor (TKR) inhibitors, but little is known about their sex-specificity. Dyskerin (DKC1), encoded by the DKC1 gene within Xq28, is a telomerase co-factor stabilizing telomerase RNA component (TERC) and overexpressed in various cancers. Here, we determined whether DKC1 and/or TERC affect ccRCC sex-differentially.

METHODS

DKC1 and TERC expression in primary ccRCC tumors was assessed using RNA sequencing and qPCR. DKC1 association with molecular alterations and overall or progression-free survival (OS or PFS) was analyzed in the TCGA cohort of ccRCC. The IMmotion 151 and 150 ccRCC cohorts were analyzed to evaluate impacts of DKC1 and TERC on Sunitinib response and PFS.

RESULTS

DKC1 and TERC expression was significantly upregulated in ccRCC tumors. High DKC1 expression predicts shorter PFS independently in female but not male patients. Tumors in the female DKC1-high group exhibited more frequent alterations in PIK3CA, MYC and TP53 genes. Analyses of the IMmotion 151 ccRCC cohort treated with the TKR inhibitor Sunitinib showed that female patients in the DKC1-high group was significantly associated with lower response rates (P = 0.021) accompanied by markedly shortened PFS (6.1 vs 14.2 months, P = 0.004). DKC1 and TERC expression correlated positively with each other, and higher TERC expression predicted poor Sunitinib response (P = 0.031) and shorter PFS (P = 0.004), too. However, DKC1 rather than TERC acted as an independent predictor (P < 0.001, HR = 2.0, 95% CI 1.480-2.704). In male patients, DKC1 expression was associated with neither Sunitinib response (P = 0.131) nor PFS (P = 0.184), while higher TERC levels did not predict response rates. Similar results were obtained from the analysis of the Sunitinib-treated IMmotion 150 ccRCC patients.

CONCLUSIONS

DKC1 serves as an independent female-specific predictor for survival and Sunitinib efficacy in ccRCC, which contribute to better understanding of the sex-biased ccRCC pathogenesis and improve personalized interventions of ccRCC.

Possible molecular mechanisms underlying the development of atherosclerosis in cancer survivors

Cancer survivors undergone treatment face an increased risk of developing atherosclerotic cardiovascular disease (CVD), yet the underlying mechanisms remain elusive. Recent studies have revealed that chemotherapy can drive senescent cancer cells to acquire a proliferative phenotype known as senescence-associated stemness (SAS). These SAS cells exhibit enhanced growth and resistance to cancer treatment, thereby contributing to disease progression. Endothelial cell (EC) senescence has been implicated in atherosclerosis and cancer, including among cancer survivors. Treatment modalities for cancer can induce EC senescence, leading to the development of SAS phenotype and subsequent atherosclerosis in cancer survivors. Consequently, targeting senescent ECs displaying the SAS phenotype hold promise as a therapeutic approach for managing atherosclerotic CVD in this population. This review aims to provide a mechanistic understanding of SAS induction in ECs and its contribution to atherosclerosis among cancer survivors. We delve into the mechanisms underlying EC senescence in response to disturbed flow and ionizing radiation, which play pivotal role in atherosclerosis and cancer. Key pathways, including p90RSK/TERF2IP, TGFβR1/SMAD, and BH4 signaling are explored as potential targets for cancer treatment. By comprehending the similarities and distinctions between different types of senescence and the associated pathways, we can pave the way for targeted interventions aim at enhancing the cardiovascular health of this vulnerable population. The insights gained from this review may facilitate the development of novel therapeutic strategies for managing atherosclerotic CVD in cancer survivors.

The regulatory feedback of inflammatory signaling and telomere/telomerase complex dysfunction in chronic inflammatory diseases

Inflammation is believed to play a role in the progression of numerous human diseases. Research has shown that inflammation and telomeres are involved in a feedback regulatory loop: inflammation increases the rate of telomere attrition, leading to telomere dysfunction, while telomere components also participate in regulating the inflammatory response. However, the specific mechanism behind this feedback loop between inflammatory signaling and telomere/telomerase complex dysfunction has yet to be fully understood. This review presents the latest findings on this topic, with a particular focus on the detailed regulation and molecular mechanisms involved in the progression of aging, various chronic inflammatory diseases, cancers, and different stressors. Several feedback loops between inflammatory signaling and telomere/telomerase complex dysfunction, including NF-κB-TERT feedback, NF-κB-RAP1 feedback, NF-κB-TERC feedback, STAT3-TERT feedback, and p38 MAPK-shelterin complex-related gene feedback, are summarized. Understanding the latest discoveries of this feedback regulatory loop can help identify novel potential drug targets for the suppression of various inflammation-associated diseases.

Harnessing Genomic Analysis to Explore the Role of Telomeres in the Pathogenesis and Progression of Diabetic Kidney Disease

The prevalence of diabetes is increasing globally, and this trend is predicted to continue for future decades. Research is needed to uncover new ways to manage diabetes and its co-morbidities. A significant secondary complication of diabetes is kidney disease, which can ultimately result in the need for renal replacement therapy, via dialysis or transplantation. Diabetic kidney disease presents a substantial burden to patients, their families and global healthcare services. This review highlights studies that have harnessed genomic, epigenomic and functional prediction tools to uncover novel genes and pathways associated with DKD that are useful for the identification of therapeutic targets or novel biomarkers for risk stratification. Telomere length regulation is a specific pathway gaining attention recently because of its association with DKD. Researchers are employing both observational and genetics-based studies to identify telomere-related genes associated with kidney function decline in diabetes. Studies have also uncovered novel functions for telomere-related genes beyond the immediate regulation of telomere length, such as transcriptional regulation and inflammation. This review summarises studies that have revealed the potential to harness therapeutics that modulate telomere length, or the associated epigenetic modifications, for the treatment of DKD, to potentially slow renal function decline and reduce the global burden of this disease.

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

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

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.

tRF-3013b inhibits gallbladder cancer proliferation by targeting TPRG1L

Background

tRNA-derived fragments (tRFs) are newly discovered noncoding RNAs and regulate tumor progression via diverse molecular mechanisms. However, the expression and biofunction of tRFs in gallbladder cancer (GBC) have not been reported yet.

Methods

The expression of tRFs in GBC was detected by tRF and tiRNA sequencing in GBC tissues and adjacent tissues. The biological function of tRFs was investigated by cell proliferation assay, clonal formation assay, cell cycle assay, and xenotransplantation model in GBC cell lines. The molecular mechanism was discovered and verified by transcriptome sequencing, fluorescence in situ hybridization (FISH), target gene site prediction, and RNA binding protein immunoprecipitation (RIP).

Results

tRF-3013b was significantly downregulated in GBC compared with para-cancer tissues. Decreased expression of tRF-3013b in GBC patients was correlated with poor overall survival. Dicer regulated the production of tRF-3013b, and its expression was positively correlated with tRF-3013b in GBC tissues. Functional experiments demonstrated that tRF-3013b inhibited GBC cell proliferation and induced cell-cycle arrest. Mechanically, tRF-3013b exerted RNA silencing effect on TPRG1L by binding to AGO3, and then inhibited NF-κB. TPRG1L overexpression could rescue the effects of tRF-3013b on GBC cell proliferation.

Conclusions

This study indicated that Dicer-induced tRF-3013b inhibited GBC proliferation by targeting TPRG1L and repressed NF-κB, pointing to tRF-3013b as a novel potential therapeutic target of GBC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s11658-022-00398-6.

TERC suppresses PD-L1 expression by downregulating RNA binding protein HuR

TERC is the RNA component of telomerase, and provides a template for TERT to synthesize telomere repeats at chromosome ends. Increasing evidence has revealed that TERC is involved in other biological processes beyond telomerase. Here, we found that the expression level of TERC is negatively correlated with PD-L1 and that ectopic expression of TERC but not TERT in ALT cells significantly inhibits PD-L1, suggesting that TERC suppresses PD-L1 expression in a telomerase-independent manner. Mechanistically, instead of regulating PD-L1 mRNA directly, TERC accelerates PD-L1 mRNA degradation by inhibiting the expression of HuR, which binds to the 3'UTR of PD-L1 mRNA and maintains its stability. We also found that the small molecule AS1842856, a FoxO1 inhibitor, promotes TERC expression and reverses the PD-L1 upregulation caused by chemotherapy, providing a potential combination cancer therapy that avoids cancer immune escape during chemotherapy.

Gene co-expression analyses of health(span) across multiple species

Health(span)-related gene clusters/modules were recently identified based on knowledge about the cross-species genetic basis of health, to interpret transcriptomic datasets describing health-related interventions. However, the cross-species comparison of health-related observations reveals a lot of heterogeneity, not least due to widely varying health(span) definitions and study designs, posing a challenge for the exploration of conserved healthspan modules and, specifically, their transfer across species. To improve the identification and exploration of conserved/transferable healthspan modules, here we apply an established workflow based on gene co-expression network analyses employing GEO/ArrayExpress data for human and animal models, and perform a comprehensive meta-study of the resulting modules related to health(span), yielding a small set of literature backed health(span) candidate genes. For each experiment, WGCNA (weighted gene correlation network analysis) was used to infer modules of genes which correlate in their expression with a 'health phenotype score' and to determine the most-connected (hub) genes (and their interactions) for each such module. After mapping these hub genes to their human orthologs, 12 health(span) genes were identified in at least two species (ACTN3, ANK1, MRPL18, MYL1, PAXIP1, PPP1CA, SCN3B, SDCBP, SKIV2L, TUBG1, TYROBP, WIPF1), for which enrichment analysis by g:profiler found an association with actin filament-based movement and associated organelles, as well as muscular structures. We conclude that a meta-study of hub genes from co-expression network analyses for the complex phenotype health(span), across multiple species, can yield molecular-mechanistic insights and can direct experimentalists to further investigate the contribution of individual genes and their interactions to health(span).

Genomic, epigenomic, and transcriptomic signatures for telomerase complex components: a pan-cancer analysis

Telomerase activation is required for malignant transformation. Recent advances in high-throughput technologies have enabled the generation of complex datasets, thus providing alternative approaches to exploring telomerase biology more comprehensively, which has proven to be challenging due to the need for laborious assays required to test for telomerase activity. To solve these issues, several groups have analyzed TCGA pan-cancer tumor datasets by investigating telomerase reverse transcriptase (TERT), the catalytic subunit for telomerase activity, or its surrogates. However, telomerase is a multiunit complex containing not only TERT, but also numerus cofactors required for telomerase function. Here we determined genomic and molecular alterations of 10 well-characterized telomerase components in the TCGA and CCLE datasets. We calculated a telomerase score (TS) based on their expression profiles and clustered tumors into low, high, and intermediate subtypes. To validate the in silico analysis result, we used immunoblotting and telomerase assays. High TS subtypes were significantly associated with stemness, proliferation, epithelial to mesenchymal transition, hyperactivation of oncogenic signaling pathways, shorter patient survival, and infiltration of dysfunctional T-cells or poor response to immunotherapy. Copy number alterations in 10 telomerase components were widespread and associated with the level of their expression. Surprisingly, primary tumors and cancer cell lines frequently displayed a homozygous deletion of the TCAB1 gene, encoding a telomerase protein essential for telomerase trafficking, assembling, and function, as previously reported. However, tumors or cells carrying a TCAB1 deletion still exhibited telomerase activity comparable to or even higher than their wildtype counterparts. Collectively, applying telomerase component-based TS in complex datasets provided a robust tool for telomerase analyses. Our findings also reveal a tight connection between telomerase and other oncogenic signaling pathways; TCAB1 may acts as a dispensable telomerase component. Moreover, TS may serve as a useful biomarker to predict patient outcomes and response to immunotherapy.

The Role of Telomerase in Breast Cancer's Response to Therapy

Currently, breast cancer appears to be the most widespread cancer in the world and the most common cause of cancer deaths. This specific type of cancer affects women in both developed and developing countries. Prevention and early diagnosis are very important factors for good prognosis. A characteristic feature of cancer cells is the ability of unlimited cell division, which makes them immortal. Telomeres, which are shortened with each cell division in normal cells, are rebuilt in cancer cells by the enzyme telomerase, which is expressed in more than 85% of cancers (up to 100% of adenocarcinomas, including breast cancer). Telomerase may have different functions that are related to telomeres or unrelated. It has been shown that high activity of the enzyme in cancer cells is associated with poor cell sensitivity to therapies. Therefore, telomerase has become a potential target for cancer therapies. The low efficacy of therapies has resulted in the search for new combined and more effective therapeutic methods, including the involvement of telomerase inhibitors and telomerase-targeted immunotherapy.

Identification of Auxiliary Biomarkers and Description of the Immune Microenvironmental Characteristics in Duchenne Muscular Dystrophy by Bioinformatical Analysis and Experiment

Background

Duchenne muscular dystrophy (DMD) is a genetic muscle disorder characterized by progressive muscle wasting associated with persistent inflammation. In this study, we aimed to identify auxiliary biomarkers and further characterize the immune microenvironment in DMD.

Methods

Differentially expressed genes (DEGs) were identified between DMD and normal muscle tissues based on Gene Expression Omnibus (GEO) datasets. Bioinformatical analysis was used to screen and identify potential diagnostic signatures of DMD which were further validated by real-time quantitative reverse transcription PCR (RT-qPCR). We also performed single-sample gene-set enrichment analysis (ssGSEA) to characterize the proportion of tissue-infiltrating immune cells to determine the inflammatory state of DMD.

Results

In total, 182 downregulated genes and 263 upregulated genes were identified in DMD. C3, SPP1, TMSB10, TYROBP were regarded as adjunct biomarkers and successfully validated by RT-qPCR. The infiltration of macrophages, CD4+, and CD8+ T cells was significantly higher (p < 0.05) in DMD compared with normal muscle tissues, while the infiltration of activated B cells, CD56dim natural killer cells, and type 17 T helper (Th17) cells was lower. In addition, the four biomarkers (C3, SPP1, TMSB10, TYROBP) were strongly associated with immune cells and immune-related pathways in DMD muscle tissues.

Conclusion

Analyses demonstrated C3, SPP1, TMSB10, and TYROBP may serve as biomarkers and enhance our understanding of immune responses in DMD. The infiltration of immune cells into the muscle microenvironment might exert a critical impact on the development and occurrence of DMD.

The road-map for establishment of a prognostic molecular marker panel in glioma using liquid biopsy: current status and future directions

Gliomas are primary intracranial tumors with defined molecular markers available for precise diagnosis. The prognosis of glioma is bleak as there is an overlook of the dynamic crosstalk between tumor cells and components of the microenvironment. Herein, different phases of gliomagenesis are presented with reference to the role and involvement of secreted proteomic markers at various stages of tumor initiation and development. The secreted markers of inflammatory response, namely interleukin-6, tumor necrosis factor-α, interferon-ϒ, and kynurenine, proliferation markers human telomerase reverse transcriptase and microtubule-associated-protein-Tau, and stemness marker human-mobility-group-AThook-1 are involved in glial tumor initiation and growth. Further, hypoxia and angiogenic factors, heat-shock-protein-70, endothelial-growth-factor-receptor-1 and vascular endothelial growth factor play a major role in promoting vascularization and tumor volume expansion. Eventually, molecules such as matrix-metalloprotease-7 and intercellular adhesion molecule-1 contribute to the degradation and remodeling of the extracellular matrix, ultimately leading to glioma progression. Our study delineates the roadmap to develop and evaluate a non-invasive panel of secreted biomarkers using liquid biopsy for precisely evaluating disease progression, to accomplish a clinical translation.

Quantifying telomeric lncRNAs using PNA-labelled RNA-Flow FISH (RNA-Flow)

Here we present a method to detect and quantify long non-coding RNAs, in particular those related to telomeres. By coupling the specificity of a peptide nucleic acid (PNA) probe with flow cytometry we have quantified cellular levels of TERRA and TERC lncRNAs in culture cell lines and PBMCs. This easy-to-use method appointed RNA-Flow allows reliable lncRNA quantification with broad applications in basic research and clinical diagnostics. In addition, the staining protocol presented here was proven useful for the detection and quantification of such lncRNAs on unfixed cells using confocal microscopy.

Telomeric-associated long non-coding RNAs TERRA and TERC can be quantified in culture cell lines and human PBMCs using peptide nucleic acid probes with flow cytometry (RNA-Flow).

Telomerase RNA TERC and the PI3K-AKT pathway form a positive feedback loop to regulate cell proliferation independent of telomerase activity

The core catalytic unit of telomerase comprises telomerase reverse transcriptase (TERT) and telomerase RNA (TERC). Unlike TERT, which is predominantly expressed in cancer and stem cells, TERC is ubiquitously expressed in normal somatic cells without telomerase activity. However, the functions of TERC in these telomerase-negative cells remain elusive. Here, we reported positive feedback regulation between TERC and the PI3K-AKT pathway that controlled cell proliferation independent of telomerase activity in human fibroblasts. Mechanistically, we revealed that TERC activated the transcription of target genes from the PI3K-AKT pathway, such as PDPK1, by targeting their promoters. Overexpression of PDPK1 partially rescued the deficiency of AKT activation caused by TERC depletion. Furthermore, we found that FOXO1, a transcription factor negatively regulated by the PI3K-AKT pathway, bound to TERC promoter and suppressed its expression. Intriguingly, TERC-induced activation of the PI3K-AKT pathway also played a critical role in the proliferation of activated CD4+ T cells. Collectively, our findings identify a novel function of TERC that regulates the PI3K-AKT pathway via positive feedback to elevate cell proliferation independent of telomerase activity and provide a potential strategy to promote CD4+ T cells expansion that is responsible for enhancing adaptive immune reactions to defend against pathogens and tumor cells.

Telomerase in Cancer: Function, Regulation, and Clinical Translation

Simple Summary

Cells undergoing malignant transformation must circumvent replicative senescence and eventual cell death associated with progressive telomere shortening that occurs through successive cell division. To do so, malignant cells reactivate telomerase to extend their telomeres and achieve cellular immortality, which is a “Hallmark of Cancer”. Here we review the telomere-dependent and -independent functions of telomerase in cancer, as well as its potential as a biomarker and therapeutic target to diagnose and treat cancer patients.

Abstract

During the process of malignant transformation, cells undergo a series of genetic, epigenetic, and phenotypic alterations, including the acquisition and propagation of genomic aberrations that impart survival and proliferative advantages. These changes are mediated in part by the induction of replicative immortality that is accompanied by active telomere elongation. Indeed, telomeres undergo dynamic changes to their lengths and higher-order structures throughout tumor formation and progression, processes overseen in most cancers by telomerase. Telomerase is a multimeric enzyme whose function is exquisitely regulated through diverse transcriptional, post-transcriptional, and post-translational mechanisms to facilitate telomere extension. In turn, telomerase function depends not only on its core components, but also on a suite of binding partners, transcription factors, and intra- and extracellular signaling effectors. Additionally, telomerase exhibits telomere-independent regulation of cancer cell growth by participating directly in cellular metabolism, signal transduction, and the regulation of gene expression in ways that are critical for tumorigenesis. In this review, we summarize the complex mechanisms underlying telomere maintenance, with a particular focus on both the telomeric and extratelomeric functions of telomerase. We also explore the clinical utility of telomeres and telomerase in the diagnosis, prognosis, and development of targeted therapies for primary, metastatic, and recurrent cancers.

Urinary Exosomal Long Noncoding RNA TERC as a Noninvasive Diagnostic and Prognostic Biomarker for Bladder Urothelial Carcinoma

Purpose

Bladder cancer is one of the most common urological malignancies worldwide, and approximately 90% of bladder cancer cases are histologically typed as bladder urothelial carcinoma (BLCA). Exosomes are 30 to 200 nm extracellular vesicles that transport microRNAs, long noncoding RNAs (lncRNAs), mRNAs, circular RNAs, and proteins across tissues and through circulation. Urinary exosomes may contain genetic information from tumor cells. Herein, we explored the clinical significance of urinary exosomal lncRNA telomerase RNA component (TERC) levels to provide an urgently needed diagnostic and prognostic biomarker for BLCA.

Materials and Methods

In this study, we used RNA-sequencing of samples from four BLCA patients and three healthy controls to identify that TERC was differentially expressed in urinary exosomes. We then used quantitative PCR in different types of clinical samples to validate the biomarker and analyzed results using receiver operating characteristic curves.

Results

We found that TERC was significantly upregulated in urinary exosomes from BLCA patients compared with those from healthy controls (P < 0.0001). Urinary exosomal TERC showed higher sensitivity (78.65%) and accuracy (77.78%) than existing indicators including nuclear matrix protein-22 and urine cytometry. Using the cut-off value 4.302, the area under the curve for urinary exosomal TERC was 0.836 (95% confidence interval: 0.768–0.891, P < 0.0001). Furthermore, this noninvasive assay could distinguish low-grade and high-grade tumors (P = 0.0153).

Conclusions

TERC is enriched in urinary exosomes from BLCA patients. Urinary exosomal TERC could become a diagnostic and prognostic biomarker for BLCA that allows clinicians to realize noninvasive detection of BLCA.

Illuminating lncRNA Function Through Target Prediction

Most of the transcribed human genome codes for noncoding RNAs (ncRNAs), and long noncoding RNAs (lncRNAs) make for the lion's share of the human ncRNA space. Despite growing interest in lncRNAs, because there are so many of them, and because of their tissue specialization and, often, lower abundance, their catalog remains incomplete and there are multiple ongoing efforts to improve it. Consequently, the number of human lncRNA genes may be lower than 10,000 or higher than 200,000. A key open challenge for lncRNA research, now that so many lncRNA species have been identified, is the characterization of lncRNA function and the interpretation of the roles of genetic and epigenetic alterations at their loci. After all, the most important human genes to catalog and study are those that contribute to important cellular functions-that affect development or cell differentiation and whose dysregulation may play a role in the genesis and progression of human diseases. Multiple efforts have used screens based on RNA-mediated interference (RNAi), antisense oligonucleotide (ASO), and CRISPR screens to identify the consequences of lncRNA dysregulation and predict lncRNA function in select contexts, but these approaches have unresolved scalability and accuracy challenges. Instead-as was the case for better-studied ncRNAs in the past-researchers often focus on characterizing lncRNA interactions and investigating their effects on genes and pathways with known functions. Here, we focus most of our review on computational methods to identify lncRNA interactions and to predict the effects of their alterations and dysregulation on human disease pathways.

Establishment of tumor inflammasome clusters with distinct immunogenomic landscape aids immunotherapy

Inflammasome signaling is a reaction cascade that influences immune response and cell death. Although the inflammasomes participate in tumorigenesis, their role as an oncogenic booster or a tumor suppresser is still controversial. Therefore, it is important to comprehensively investigate the inflammasome signaling status across various cancers to clarify its clinical and therapeutic significance.

Methods: A total of 9881 patients across 33 tumor types from The Cancer Genome Atlas database were included in this study. Five gene sets were identified to step-wisely profile inflammasome signaling. Unsupervised clustering was used for sample classification based on gene set enrichment. Machine learning and in vitro and in vivo experiments were used to confirm the implications of inflammasome classification.

Results: A hundred and forty-one inflammasome-signaling-related genes were identified to construct five gene sets representing the sensing, activation, and termination steps of the inflammasome signaling. Six inflammasome clusters were robustly established with distinct molecular, biological, clinical, and therapeutic features. Importantly, clusters with inflammasome signaling activation were found to be immunosuppressive and resistant to ICB treatment. Inflammasome inhibition reverted the therapeutic failure of ICB in inflammasome-activated tumors. Moreover, based on the proposed classification and therapeutic implications, an open website was established to provide tumor patients with comprehensive information on inflammasome signaling.

Conclusions: Our study conducted a systematical investigation on inflammasome signaling in various tumor types. These findings highlight the importance of inflammasome evaluation in tumor classification and provide a foundation for improving relevant therapeutic regimens.

Novel molecular panel for evaluating systemic inflammation and survival in therapy naïve glioma patients

BACKGROUND

Inflammation is crucial to tumor progression. A traumatic event at a specific site in the brain activates the signaling molecules, which triggers inflammation as the initial response within the tumor and its surroundings. The educated immune cells and secreted proteins then initiate the inflammatory cascade leading to persistent chronic inflammation. Therefore, estimation of the circulating inflammatory indicators kynurenine (KYN), interleukin-6 (IL-6), tissue-inhibitor of matrix-metalloproteinase-1 and human telomerase reverse transcriptase (hTERT) along with neutrophil-lymphocyte ratio (NLR) has prognostic value.

AIM

To assess the utility of chosen inflammatory marker panel in estimating systemic inflammation.

METHODS

The chosen markers were quantitatively evaluated in 90 naive, molecularly sub-typed plasma samples of glioma. A correlation between the markers and confounders was assessed to establish their prognostication power. Follow-up on the levels of the indicators was done 3-mo post-surgery. To establish the validity of circulating KYN, it was also screened qualitatively by dot-immune-assay and by immunofluorescence-immunohistochemistry in tumor tissues.

RESULTS

Median values of circulating KYN, IL-6, hTERT, tissue-inhibitor of matrix-metalloproteinase-1 and NLR in isocitrate-dehydrogenase-mutant/wildtype and within the astrocytic sub-groups were estimated, which differed from controls, reaching statistical significance (P < 0.0001). All markers negatively correlated with mortality (P < 0.0001). Applying combination-statistics, the panel of KYN, IL-6, hTERT and NLR achieved higher sensitivity and specificity (> 90%) than stand-alone markers, to define survival. The inflammatory panel could discriminate between WHO grades, and isocitrate-dehydrogenase-mutant/wildtype and define differential survival between astrocytic isocitrate-dehydrogenase-mutant/wildtype. Therefore, its assessment for precise disease prognosis is indicated. Association of KYN with NLR, IL-6 and hTERT was significant. Cox-regression described KYN, IL-6, NLR, and hTERT as good prognostic markers, independent of confounders. Multivariate linear-regression analysis confirmed the association of KYN and hTERT with inflammation marker IL-6.There was a concomitant significant decrease in their levels in a 3-mo follow-up.

CONCLUSION

The first evidence-based study of circulating-KYN in molecularly defined gliomas, wherein the tissue expression was found to be concomitant with plasma levels. A non-invasive model for assessing indicators of chronic systemic inflammation is proposed.

Genetic, Environmental and Lifestyle Determinants of Accelerated Telomere Attrition as Contributors to Risk and Severity of Multiple Sclerosis

Telomeres are protective structures at the ends of linear chromosomes. Shortened telomere lengths (TL) are an indicator of premature biological aging and have been associated with a wide spectrum of disorders, including multiple sclerosis (MS). MS is a chronic inflammatory, demyelinating and neurodegenerative disease of the central nervous system. The exact cause of MS is still unclear. Here, we provide an overview of genetic, environmental and lifestyle factors that have been described to influence TL and to contribute to susceptibility to MS and possibly disease severity. We show that several early-life factors are linked to both reduced TL and higher risk of MS, e.g., adolescent obesity, lack of physical activity, smoking and vitamin D deficiency. This suggests that the mechanisms underlying the disease are connected to cellular aging and senescence promoted by increased inflammation and oxidative stress. Additional prospective research is needed to clearly define the extent to which lifestyle changes can slow down disease progression and prevent accelerated telomere loss in individual patients. It is also important to further elucidate the interactions between shared determinants of TL and MS. In future, cell type-specific studies and advanced TL measurement methods could help to better understand how telomeres may be causally involved in disease processes and to uncover novel opportunities for improved biomarkers and therapeutic interventions in MS.

Immune Microenvironment Signatures as Biomarkers to Predict Early Recurrence of Stage Ia-b Lung Cancer

Introduction

Approximately 30% of patients diagnosed with stage Ia-b NSCLC die of recurrent disease after surgery. This study aimed to identify immune-related biomarkers that might predict tumor recurrence in stage Ia-b NSCLC within 40 months after curative resection.

Methods

Gene expression data of stage Ia-b NSCLC samples was retrieved from the TCGA database, the GEO databases, and the Second Xiangya hospital (XXEYY) database. 22 types of tumors infiltrating immune cells and the expression of immune-associated genes were investigated using CIBERSORT, immunohistochemical staining, and GSEA analyses in a total of 450 patients (80 in the training cohort and 370 in the validation cohorts). Recurrence-related immune features were selected based on the LASSO Cox regression model.

Results

High density of Tregs, Macrophages M0 and M1 cell could be observed in recurrence group while the memory B cell was more frequently enriched in controls, yet Tregs alone was significantly associated with tumor early recurrence in TCGA cohort, XYEYY cohort and GSE37745 dataset. A handful of immune-related genes were identified in the recurrence group. Based on Lasso regression analysis, the expressions of five immune-related genes, RLTPR, SLFN13, MIR4500HG, HYDIN and TPRG1 were closely correlated with tumor early recurrence. In the training cohort (TCGA), the combination of these five genes has sensitivity and specificity of 85% and 85%, with AUC of 0.91 (95% CI 0.84-0.98) for lung cancer early recurrence prediction, whereas in validation cohorts, the sensitivity and specificity using this panel was 61-89% and 54-82%, with AUC of 0.62-0.84.

Conclusion

Our study demonstrated that the immune microenvironment signatures were closely related to tumor early recurrence. Compared to tumor-infiltrating lymphocytes, the expression of five immune-related genes could be robust biomarkers to predict early recurrence of stage Ia-b NSCLC after curative resection.

Cellular Reprogramming and Immortality: Expression Profiling Reveals Putative Genes Involved in Turritopsis dohrnii's Life Cycle Reversal

To gather insight on the genetic network of cell reprogramming and reverse development in a nonmodel cnidarian system, we produced and annotated a transcriptome of the hydrozoan Turritopsis dohrnii, whose medusae respond to damage or senescence by metamorphosing into a juvenile stage (the polyp), briefly passing through an intermediate and uncharacterized stage (the cyst), where cellular transdifferentiation occurs. We conducted sequential and pairwise differential gene expression (DGE) analyses of the major life cycle stages involved in the ontogenetic reversal of T. dohrnii. Our DGE analyses of sequential stages of T. dohrnii’s life cycle stages show that novel and characterized genes associated with aging/lifespan, regulation of transposable elements, DNA repair, and damage response, and Ubiquitin-related processes, among others, were enriched in the cyst stage. Our pairwise DGE analyses show that, when compared with the colonial polyp, the medusa is enriched with genes involved in membrane transport, the nervous system, components of the mesoglea, and muscle contraction, whereas genes involved in chitin metabolism and the formation of the primary germ layers are suppressed. The colonial polyp and reversed polyp (from cyst) show significant differences in gene expression. The reversed polyp is enriched with genes involved in processes such as chromatin remodeling and organization, matrix metalloproteinases, and embryonic development whereas suppressing genes involved in RAC G-protein signaling pathways. In summary, we identify genetic networks potentially involved in the reverse development of T. dohrnii and produce a transcriptome profile of all its life cycle stages, and paving the way for its use as a system for research on cell reprogramming.

Leukocyte Telomere Length in Patients with Multiple Sclerosis and Its Association with Clinical Phenotypes

Aging is a significant factor influencing the course of multiple sclerosis (MS). Accelerated telomere attrition is an indicator of premature biological aging and a potential contributor to various chronic diseases, including neurological disorders. However, there is currently a lack of studies focusing on telomere lengths in patients with MS. We measured the average leukocyte telomere length (LTL) in biobanked DNA samples of 40 relapsing-remitting MS patients (RRMS), 20 primary progressive MS patients (PPMS), and 60 healthy controls using a multiplex quantitative polymerase chain reaction method. Changes in LTL over a period of >10 years were evaluated in a subset of 10 patients. Association analyses of baseline LTL with the long-term clinical profiles of the patients were performed using inferential statistical tests and regression models adjusted for age and sex. The cross-sectional analysis revealed that the RRMS group was characterized by a significantly shorter relative LTL, on average, as compared to the PPMS group and controls. Shorter telomeres at baseline were also associated with a higher conversion rate from RRMS to secondary progressive MS (SPMS) in the 10-year follow-up. The LTL decrease over time was similar in RRMS patients and PPMS patients in the longitudinal analysis. Our data suggest a possible contributory role of accelerated telomere shortening in the pathobiology of MS. The interplay between disease-related immune system alterations, immunosenescence, and telomere dynamics deserves further investigation. New insights into the mechanisms of disease might be obtained, e.g., by exploring the distribution of telomere lengths in specific blood cell populations.

Insights into the Links between MYC and 3D Chromatin Structure and Epigenetics Regulation: Implications for Cancer Therapy

MYC is embedded in the transcriptional oasis of the 8q24 gene desert. A plethora of genomic elements has roles in MYC aberrant expression in cancer development by interacting with transcription factors and epigenetics regulators as well as altering the structure of chromatin at the MYC locus and tissue-specific long-range enhancer-promoter contacts. Furthermore, MYC is a master regulator of several human cancers by modulating the transcription of numerous cancer-related genes through epigenetic mechanisms. This review provides a comprehensive overview of the three-dimensional genomic organization around MYC and the role of epigenetic machinery in transcription and function of MYC as well as discusses various epigenetic-targeted therapeutic strategies in MYC-driven cancers.

Long non-coding RNAs at work on telomeres: Functions and implications in cancer therapy

Long non-coding RNAs (lncRNAs) are known to regulate various biological processes including cancer. Cancer cells possess limitless replicative potential which is attained by telomere length maintenance while normal somatic cells have a limited lifespan because their telomeres shorten with every cell division ultimately triggering replicative senescence. Two lncRNAs have been observed to play a key role in telomere length maintenance. First is the lncRNA TERC (telomerase RNA component) which functions as a template for telomeric DNA synthesis in association with telomerase reverse transcriptase (TERT) which serves as the catalytic component. Together they constitute the telomerase complex which functions as a reverse transcriptase to elongate telomeres. Second lncRNA that helps in regulating telomere length is the telomeric repeat-containing RNA (TERRA) which is transcribed from the subtelomeric region and extends to the telomeric region. TERC and TERRA exhibit important functions in cancer with implications in precision oncology. In this review, we discuss various aspects of these important lncRNAs in humans and their role in cancer along with recent advancements in their anticancer therapeutic application.

Telomere-related Markers for Cancer

Telomeres are structurally nucleoprotein complexes at termini of linear chromosomes and essential to chromosome stability/integrity. In normal human cells, telomere length erodes progressively with each round of cell divisions, which serves as an important barrier to uncontrolled proliferation and malignant transformation. In sharp contrast, telomere maintenance is a key feature of human malignant cells and required for their infinite proliferation and maintenance of other cancer hallmarks as well. Thus, a telomere-based anti-cancer strategy has long been suggested. However, clinically efficient and specific drugs targeting cancer telomere-maintenance have still been in their infancy thus far. To achieve this goal, it is highly necessary to elucidate how exactly cancer cells maintain functional telomeres. In the last two decades, numerous studies have provided profound mechanistic insights, and the identified mechanisms include the aberrant activation of telomerase or the alternative lengthening of telomere pathway responsible for telomere elongation, dysregulation and mutation of telomere-associated factors, and other telomere homeostasis-related signaling nodes. In the present review, these various strategies employed by malignant cells to regulate their telomere length, structure and function have been summarized, and potential implications of these findings in the rational development of telomere-based cancer therapy and other clinical applications for precision oncology have been discussed.

Telomere Length Dynamics and DNA Damage Responses Associated with Long-Duration Spaceflight

Telomere length dynamics and DNA damage responses were assessed before, during, and after one-year or shorter duration missions aboard the International Space Station (ISS) in a comparatively large cohort of astronauts (n = 11). Although generally healthy individuals, astronauts tended to have significantly shorter telomeres and lower telomerase activity than age- and sex-matched ground controls before and after spaceflight. Although telomeres were longer during spaceflight irrespective of mission duration, telomere length shortened rapidly upon return to Earth, and overall astronauts had shorter telomeres after spaceflight than they did before; inter-individual differences were identified. During spaceflight, all crewmembers experienced oxidative stress, which positively correlated with telomere length dynamics. Significantly increased frequencies of chromosomal inversions were observed during and after spaceflight; changes in cell populations were also detected. We propose a telomeric adaptive response to chronic oxidative damage in extreme environments, whereby the telomerase-independent Alternative Lengthening of Telomeres (ALT) pathway is transiently activated in normal somatic cells.

A mouse tissue atlas of small noncoding RNA

We report a systematic unbiased analysis of small RNA molecule expression in 11 different tissues of the model organism mouse. We discovered uncharacterized noncoding RNA molecules and identified that ∼30% of total noncoding small RNA transcriptome are distributed across the body in a tissue-specific manner with some also being sexually dimorphic. Distinct distribution patterns of small RNA across the body suggest the existence of tissue-specific mechanisms involved in noncoding RNA processing.

Small noncoding RNAs (ncRNAs) play a vital role in a broad range of biological processes both in health and disease. A comprehensive quantitative reference of small ncRNA expression would significantly advance our understanding of ncRNA roles in shaping tissue functions. Here, we systematically profiled the levels of five ncRNA classes (microRNA [miRNA], small nucleolar RNA [snoRNA], small nuclear RNA [snRNA], small Cajal body-specific RNA [scaRNA], and transfer RNA [tRNA] fragments) across 11 mouse tissues by deep sequencing. Using 14 biological replicates spanning both sexes, we identified that ∼30% of small ncRNAs are distributed across the body in a tissue-specific manner with some also being sexually dimorphic. We found that some miRNAs are subject to “arm switching” between healthy tissues and that tRNA fragments are retained within tissues in both a gene- and a tissue-specific manner. Out of 11 profiled tissues, we confirmed that brain contains the largest number of unique small ncRNA transcripts, some of which were previously annotated while others are identified in this study. Furthermore, by combining these findings with single-cell chromatin accessibility (scATAC-seq) data, we were able to connect identified brain-specific ncRNAs with their cell types of origin. These results yield the most comprehensive characterization of specific and ubiquitous small RNAs in individual murine tissues to date, and we expect that these data will be a resource for the further identification of ncRNAs involved in tissue function in health and dysfunction in disease.

Human Cytomegalovirus Long Non-coding RNA1.2 Suppresses Extracellular Release of the Pro-inflammatory Cytokine IL-6 by Blocking NF-κB Activation

Long non-coding RNAs (lncRNAs) are transcripts of >200 nucleotides that are not translated into functional proteins. Cellular lncRNAs have been shown to act as regulators by interacting with target nucleic acids or proteins and modulating their activities. We investigated the role of RNA1.2, which is one of four major lncRNAs expressed by human cytomegalovirus (HCMV), by comparing the properties of parental virus in vitro with those of deletion mutants lacking either most of the RNA1.2 gene or only the TATA element of the promoter. In comparison with parental virus, these mutants exhibited no growth defects and minimal differences in viral gene expression in human fibroblasts. In contrast, 76 cellular genes were consistently up- or down-regulated by the mutants at both the RNA and protein levels at 72 h after infection. Differential expression of the gene most highly upregulated by the mutants (Tumor protein p63-regulated gene 1-like protein; TPRG1L) was confirmed at both levels by RT-PCR and immunoblotting. Consistent with the known ability of TPRG1L to upregulate IL-6 expression via NF-κB stimulation, RNA1.2 mutant-infected fibroblasts were observed to upregulate IL-6 in addition to TPRG1L. Comparable surface expression of TNF receptors and responsiveness to TNF-α in cells infected by the parental and mutant viruses indicated that activation of signaling by TNF-α is not involved in upregulation of IL-6 by the mutants. In contrast, inhibition of NF-κB activity and knockdown of TPRG1L expression reduced the extracellular release of IL-6 by RNA1.2 mutant-infected cells, thus demonstrating that upregulation of TPRG1L activates NF-κB. The levels of MCP-1 and CXCL1 transcripts were also increased in RNA1.2 mutant-infected cells, further demonstrating the presence of active NF-κB signaling. These results suggest that RNA1.2 plays a role in manipulating intrinsic NF-κB-dependent cytokine and chemokine release during HCMV infection, thereby impacting downstream immune responses.

Human Telomerase RNA: Telomerase Component or More?

Telomerase is a ribonucleoprotein complex that maintains the lengths of telomeres. Most studies of telomerase function have focused on the involvement of telomerase activation in the immortalization of cancer cells and cellular rejuvenation. However, some studies demonstrated that the results do not meet expectations for telomerase action in telomere maintenance. Recent results give reason to think that major telomerase components-the reverse transcriptase protein subunit and telomerase RNA-may participate in many cellular processes, including the regulation of apoptosis and autophagy, cell survival, pro-proliferative effects, regulation of gene expression, and protection against oxidative stress. However, the difficulties faced by scientist when researching telomerase component functions often reduce confidence in the minor effects observed in experiments. In this review, we focus on the analysis of the functions of telomerase components (paying more attention to the telomerase RNA component), both as a complex and as independent components, providing effects that are not associated with telomerase activity and telomere length maintenance. Despite the fact that the data on alternative roles of telomerase components look illusory, it would be wrong to completely reject the possibility of their involvement in other biological processes excluded from research/discussion. Investigations to improve the understanding of every aspect of the functioning of telomerase components will provide the basis for a more precise development of approaches to regulate cellular homeostasis, which is important for carcinogenesis and aging.

The telomerase gene polymorphisms, but not telomere length, increase susceptibility to primary glomerulonephritis/end stage renal diseases in females

Background

Primary glomerulonephritis (GN) is the leading cause of chronic kidney disease (CKD) and frequently progresses into end stage renal diseases (ESRDs). Shorter leukocyte telomere length (LTL) has been implicated in the CKD susceptibility and diminished kidney function, however, it is unclear whether the variants in telomerase genes contribute to risk to GN/CKD/ESRD. Here we address this issue by determining their association with the genetic variants of rs12696304 at the telomerase RNA component (TERC) and rs2736100 at the telomerase reverse transcriptase (TERT) loci.

Methods

The study includes 769 patients (243 primary GN-derived CKD and 526 ESRD cases) and sex-/age-matched healthy controls. Genomic DNA was extracted from peripheral blood of both controls and patients. Genotyping of rs12696304 and rs2736100 variants was carried out using PCR-based assays. Leukocyte telomere length (LTL) was determined using quantitative PCR (qPCR).

Results

A significantly higher frequency of TERC rs12696304 G allele was observed in patients and associated with increased disease risk (C vs G: OR = 1.334, 95% CI 1.112–1.586, P = 0.001; CC + GC vs GG: OR = 1.334, 95% CI 1.122–1.586, P = 0.001). Further analyses showed that such significant differences were only present between female controls and patients (C vs G: OR = 1.483, 95% CI 1.140–1.929, P = 0.003; CC + GC vs CC: OR = 1.692, 95% CI 1.202–2.383, P = 0.003), but not males. There were no differences in rs2736100 variants between controls and patients, but female ESRD patients carried significantly higher C allele frequencies than did female controls (A vs C: OR = 1.306, 95% CI 1.005–1.698, P = 0.046; AA vs CC: OR = 1.781, 95% CI 1.033–3.070, P = 0.037). There was no difference in LTL between controls and patients.

Conclusions

Our results reveal that the TERC rs12696304 and TERT rs2736100 polymorphisms, but not LTL per se, contribute to GN/CDK/ESRD risk.

The molecular biomarkers of vascular aging and atherosclerosis: telomere length and mitochondrial DNA4977 common deletion

Age is the dominant risk factor for the most prevalent atherosclerotic vascular diseases, including coronary artery disease, myocardial infarction, cerebrovascular disease and stroke. In human, telomere erosion and mitochondrial DNA (mtDNA) damage play a central role in the mechanisms leading to cellular aging decline. This review summarizes the most relevant findings on the role of telomere shortening and the common mtDNA⁴⁹⁷⁷ deletion in the progression and evolution of atherosclerosis by combining insight from experimental models and human clinical studies. The current evidence shows a link between telomere erosion and compromised mitochondrial function and provides a new perspective regarding their potential role as clinical biomarkers and therapeutic targets.

Practical Guidance in Genome-Wide RNA:DNA Triple Helix Prediction

Long noncoding RNAs (lncRNAs) play a key role in many cellular processes including chromatin regulation. To modify chromatin, lncRNAs often interact with DNA in a sequence-specific manner forming RNA:DNA triple helices. Computational tools for triple helix search do not always provide genome-wide predictions of sufficient quality. Here, we used four human lncRNAs (MEG3, DACOR1, TERC and HOTAIR) and their experimentally determined binding regions for evaluating triplex parameters that provide the highest prediction accuracy. Additionally, we combined triplex prediction with the lncRNA secondary structure and demonstrated that considering only single-stranded fragments of lncRNA can further improve DNA-RNA triplexes prediction.

Mitochondria, Telomeres and Telomerase Subunits

Mitochondrial functions and telomere functions have mostly been studied independently. In recent years, it, however, has become clear that there are intimate links between mitochondria, telomeres, and telomerase subunits. Mitochondrial dysfunctions cause telomere attrition, while telomere damage leads to reprogramming of mitochondrial biosynthesis and mitochondrial dysfunctions, which has important implications in aging and diseases. In addition, evidence has accumulated that telomere-independent functions of telomerase also exist and that the protein component of telomerase TERT shuttles between the nucleus and mitochondria under oxidative stress. Our previously published data show that the RNA component of telomerase TERC is also imported into mitochondria, processed, and exported back to the cytosol. These data show a complex regulation network where telomeres, nuclear genome, and mitochondria are co-regulated by multi-localization and multi-function proteins and RNAs. This review summarizes the connections between mitochondria and telomeres, the mitochondrion-related functions of telomerase subunits, and how they play a role in crosstalk between mitochondria and the nucleus.