Studies have proven that as competing endogenous RNAs (ceRNAs), long non-coding RNAs (lncRNAs) play vital roles in regulating RNA transcripts in ischemic stroke. It has been reported that TTTY15, a lncRNA, is dysregulated in cardiomyocytes after ischemic injury. We intended to explore the potential regulating mechanism of TTTY15 in ischemic stroke.
TTTY15 and miR-520a-3p levels in vivo were measured in the cerebral ischemia/reperfusion (I/R) model. Cell apoptosis was measured by flow cytometry. To manifest TTTY15 functions in I/R injury, Neuro 2a (N2a) cells were exposed to oxygen-glucose deprivation/reoxygenation (OGD/R) and treated with si-NC, pcDNA3.1-NC, si-TTTY15 or pcDNA3.1-TTTY15.
TTTY15 expression was elevated and miR-520a-3p expression was declined in mouse brains exposed to I/R and in N2a cells exposed to OGD/R. Bioinformatics analyses predicted the binding sites of miR-520a-3p in the 3\'-UTRs of interferon regulatory factor 9 (IRF9) and TTTY15. Luciferase reporter assay exhibited that TTTY15 bound to miR-520a-3p directly and IRF9 was targeted by miR-520a-3p. MiR-520a-3p overexpression diminished N2a cell apoptosis caused by OGD/R. TTTY15 overexpression antagonized the inhibitory impacts of miR-520a-3p on IRF9 expression and apoptosis after OGD/R, while TTTY15 knockdown enhanced the inhibitory impacts of miR-520a-3p. Additionally, TTTY15 knockdown alleviated brain damages and neurological deficits induced by I/R in vivo. Our results revealed that TTTY15 modulated IRF9 via acting as a ceRNA for miR-520a-3p.
The study revealed the roles of TTTY15/miR-520a-3p/IRF9 signaling pathway in regulating cerebral ischemia/reperfusion injury.

The present study is aimed to investigate the regulatory effects and related mechanism of long non-coding RNA testis-specific transcript, Y-linked 15 (TTTY15) in gastric carcinoma (GC) cell proliferation, migration, invasion, apoptosis and epithelial-mesenchymal transition (EMT). TTTY15 expression in GC tissue samples and cells was detected by quantitative real-time PCR (qRT-PCR), and the correlation between TTTY15 expression and GC clinicopathological indicators was analyzed. Cell counting kit-8 (CCK-8), BrdU, flow cytometry and Transwell assays were performed for detecting GC cell proliferation, migration, invasion and apoptosis. Western blot was performed for detecting the expressions of EMT-associated proteins (N-cadherin and E-cadherin), Wnt family member 1 (Wnt1) protein and β-catenin protein. Bioinformatics analysis was conducted to predict, and RNA immunoprecipitation (RIP) assay and dual-luciferase reporter gene assay were performed to verify the targeted relationships of microRNA let-7a-5p (let-7a-5p) with TTTY15 and Wnt1 mRNA 3\'UTR. It was found that TTTY15 expression was significantly up-regulated in GC tissues and cells, and was associated with advanced TNM stage and poor tumor differentiation. TTTY15 overexpression promoted GC cell proliferation, migration and invasion, the expressions of N-cadherin, Wnt1 and β-catenin protein, and inhibited the apoptosis and E-cadherin expression, while knocking down TTTY15 had the opposite effects. TTTY15 directly targeted let-7a-5p and negatively regulated its expression. Wnt1 was the target gene of let-7a-5p, and TTTY15 could indirectly and positively regulate Wnt1 expression. In conclusion, TTTY15 promotes GC progression, by regulating the let-7a-5p/Wnt1 axis to activate the Wnt/β-catenin pathway.

Acute myocardial infarction (AMI) is a ubiquitous cardiovascular disease ensuing adverse prognosis caused by myocardial necrosis. Effective and rapid diagnosis of AMI is essential to following treatment in clinical practice while the existed biomarkers have inherent limitations. Consequently, exploration of novel biomarkers is needed. Long noncoding RNA (lncRNA) emerges as the upcoming biomarkers adopted in clinical use, and we aim at investigating the diagnostic power of lncRNA TTTY15 and HULC in AMI patients.
We measured lncRNA level in 80 AMI patients and 36 healthy volunteers in discovering cohort and 50 AMI patients and 20 healthy volunteers in verification cohort with quantitative RT-PCR method. Receiver operating characteristic (ROC) analysis was administered to detect the diagnostic power of selected lncRNAs. Regression and correlation analyses were performed to explore the related factors.
ROC analysis reveals the superiority of TTTY15 and HULC as biomarkers against conventional AMI biomarkers CKMB (AUC of TTTY15: 0.915 versus CKMB: 0.768 versus TnT: 0.869); AUC of HULC: 0.905 versus CKMB: 0.768 versus TnT: 0.869). Regression and correlation analysis indicates that TTTY15 and HULC may be one of the contributing factors to AMI and related to accepted risk factors.
Our results revealed the diagnostic potency of lncRNA TTTY15 and HULC, and they could also be treated as novel therapeutic targets in AMI therapy, hinting inspiration to the cardiologist in clinical practice.

Myocardial ischemia/reperfusion (I/R) injury greatly contributes to myocardial tissue damage in patients with coronary disease, which eventually leads to heart failure. Long noncoding RNAs (lncRNAs) have an emerging role in the process of myocardial I/R injury. Our previous work revealed the protective role of miR-374a-5p against myocardial I/R injury. In this study, we explored the role of lncRNA TTTY15 and its potential interaction mechanisms with miR-374a-5p in myocardial I/R injury. The expression of TTTY15 was increased both in vitro and in vivo after myocardial I/R injury models according to quantitative real-time polymerase chain reaction. Various assays were conducted to evaluate the regulatory relationship among TTTY15, miR-374a-5p, FOXO1, and autophagy in H9c2 and HL-1 cells. The results showed that TTTY15 suppresses autophagy and myocardial I/R injury by targeting miR-374a-5p. We found that TTTY15 regulates miR-374a-5p, thus affecting FOXO1 expression and autophagy in myocytes during I/R. Furthermore, in an in vivo mouse model of myocardial I/R injury, suppression of TTTY15 successfully alleviated myocardial I/R injury. Our results reveal a novel feedback mechanism in which TTTY15 regulates miRNA processing and a potential target in myocardial I/R injury. TTTY15 is a promising therapeutic target for treating myocardial I/R injury.

Noncoding RNAs are interweaved in pathological processes in myocardial ischemia (MI), such as long noncoding RNA (lncRNA) and microRNAs (miRNAs). The aim of this study was to figure out the role of Testis-specific transcript Y-linked 15 (TTTY15) and let-7i-5p in cell model of MI in cardiomyocytes. Hypoxia-induced cell injury was assessed by Cell counting kit 8 assay, flow cytometry, commercial kits and western blotting. As a result, hypoxia stress induced inhibition on cell proliferation, glucose uptake, and ATP production, and promotion on apoptosis, lactate dehydrogenase (LDH) release, and lactic acid production in human cardiomyocyte AC16 cells. During hypoxia injury, expression of TTTY15 and let-7i-5p was measured by real-time quantitative polymerase chain reaction, and TTTY15 was upregulated, accompanied with let-7i-5p downregulation. Functionally, either silencing TTTY15 or overexpressing let-7i-5p could attenuate hypoxia-induced apoptosis and mitochondrial energy metabolism dysfunction in AC16 cells. Moreover, there was an interaction between TTTY15 and let-7i-5p via target binding, as evidenced by dual-luciferase reporter assay and RNA immunoprecipitation assay. Knockdown of let-7i-5p could counteract the protective role of TTTY15 deletion in hypoxic AC16 cells. Meanwhile, toll-like receptor 3 (TLR3)/nuclear factor-kappa B (NF-κB) signaling was validated by western blotting. Expression of TLR3, tumor necrosis factor receptor-associated factor 6 (TRAF6) and phosphorylated p65 was promoted in hypoxic AC16 cells, which was abrogated by TTTY15 silencing along with let-7i-5p upregulation. Collectively, TTTY15 knockdown protects cardiomyocytes against hypoxia-induced apoptosis and mitochondrial energy metabolism dysfunction in vitro through let-7i-5p/TLR3/NF-κB pathway to suppress.

Acute myocardial infarction (AMI) is a serious threat to human health. Long non-coding RNAs (lncRNAs) are known to be involved in the progression of AMI. The objective of this paper was to explore the functional effect of lncRNA testis-specific transcript Y-linked 15 (TTTY15) on hypoxia-induced cardiomyocyte injury. Human cardiomyocytes AC16 were cultured under hypoxic conditions to induce cardiomyocyte injury. Quantitative real-time polymerase chain reaction (qRT-PCR) was employed to check the expression of TTTY15, microRNA let-7b, and Mitogen-activated protein kinase 6 (MAPK6). Western blot was implemented for protein detection. Cell viability and apoptosis were examined by Cell counting kit-8 (CCK-8) assay and flow cytometry, respectively. The target association among TTTY15, let-7b, and MAPK6 was validated by dual-luciferase reporter assay, pull-down assay and RNA immunoprecipitation (RIP) assay. We found that the abundances of TTTY15 and MAPK6 were elevated, while let-7b level declined in hypoxia-induced AC16 cells. Knockdown of TTTY15 increased cell viability, and inhibited apoptosis of hypoxia-induced AC16 cells. TTTY15 bound to and inversely regulated let-7b. Likewise, MAPK6 was a target of let-7b and was negatively regulated by let-7b. Silencing of TTTY15 ameliorated the impact of let-7b downregulation or MAPK6 upregulation on hypoxia-induced cardiomyocyte injury. TTTY15 modulated MAPK6 enrichment by sponging let-7b. In conclusion, knockdown of TTTY15 suppressed hypoxia-induced cardiomyocyte injury through the let-7b/MAPK6 axis.

Acute myocardial infarction (AMI) can lead to myocardial injury, and long non-coding RNA (lncRNA) has been found to play an important regulatory role in the process of myocardial injury. However, the role and potential mechanisms of lncRNA testis-specific transcript Y-linked 15 (TTTY15) in AMI-induced myocardial injury has not been fully elucidated. Hydrogen peroxide (H2O2)-induced AMI cell model was built and AMI mice model were constructed. Relative expression levels of TTTY15, miR-98-5p and C-reactive protein (CRP) were determined by quantitative real-time PCR (qRT-PCR). Cell counting kit 8 (CCK8) assay, flow cytometry and enzyme-linked immunosorbent assay (ELISA) were employed to assess cell viability, apoptosis, inflammatory response and oxidative stress. Western blot (WB) analysis was used to assess the protein expression levels. The mechanism of TTTY15 was confirmed by dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay. Our results revealed that TTTY15 was upregulated and miR-98-5p was downregulated in AMI patients and H2O2-stimulated myocardial cells. Knockdown of TTTY15 could alleviate H2O2-stimulated myocardial cell injury in vitro and AMI progression in vivo. Bioinformatics analysis and the rescue experiments confirmed that TTTY15 positively regulated H2O2-induced myocardial cell injury via regulating CRP by sponging miR-98-5p. Our research proposed that lncRNA TTTY15 promoted myocardial cell injury by regulating the miR-98-5p/CRP axis, suggesting that TTTY15 might be a potential target for alleviating AMI-caused myocardial cell injury.

Gender affects cancer susceptibility. Currently, there are only a few studies on Y chromosome-linked long noncoding RNAs (lncRNAs), and the potential association between lncRNAs and cancers in males has not been fully elucidated. Here, we examined the expression of testis-specific transcript Y-linked 15 (TTTY15) in 37 males with non-small cell lung cancer (NSCLC), and performed circular chromosome conformation capture with next-generation sequencing to determine the genomic interaction regions of the TTTY15 gene. Our results showed that the expression levels of TTTY15 were lower in NSCLC tissues. Lower TTTY15 expression levels were associated with Tumor-Node-Metastasis (TNM) stage. A TTTY15 knockdown promoted malignant transformation of NSCLC cells. Based on the bioinformatics analysis of circular chromosome conformation capture data, we found that T-box transcription factor 4 (TBX4) may be a potential target gene of TTTY15. The RNA immunoprecipitation and chromatin immunoprecipitation results showed that TTTY15 may interact with DNA (cytosine-5)-methyltransferase 3A (DNMT3A), and the TTTY15 knockdown increased the binding of DNMT3A to the TBX4 promoter. We concluded that low TTTY15 expression correlates with worse prognosis among patients with NSCLC. TTTY15 promotes TBX4 expression via DNMT3A-mediated regulation. The identification of lncRNAs encoded by male-specific genes may help to identify potential targets for NSCLC therapy.

The link between prostate cancer (PCa) development and aberrant expression of genes located on the Y chromosome remains unclear.
To identify Y-chromosomal long noncoding RNAs (lncRNAs) with critical roles in PCa and to clarify the corresponding mechanisms.
Aberrantly expressed lncRNAs on the Y chromosome were identified using transcriptome analysis of PCa clinical samples and cell lines. Biological functions and molecular mechanisms of the lncRNAs were revealed using in vitro and in vivo experimental methods.
Experiments and outcome measurements were performed in duplicate or triplicate. Wilcoxon signed-rank test was employed for comparison of RNA levels in clinical cohorts. Analysis of variance was employed for comparisons among multiple groups.
In most patients with PCa, TTTY15 was the most elevated lncRNA located on the Y chromosome. Knockout of this lncRNA by two different CRISPR-Cas9 strategies suppressed PCa cell growth both in vitro and in vivo. TTTY15 promoted PCa by sponging the microRNA let-7, consequently increasing CDK6 and FN1 expression. FOXA1 is an upstream regulatory factor of TTTY15 transcription.
The Y-chromosomal lncRNA TTTY15 was upregulated in most PCa tissues and could promote PCa progression by sponging let-7.
We found that TTTY15 levels were frequently elevated in prostate cancer (PCa) tissues compared with those in paracancerous normal tissues in a large group of PCa patients, and we observed a tumour suppressive effect after TTTY15 knockout using CRISPR/Cas9. These results may have therapeutic implications for PCa patients.