Tumor-suppressive activities for pogo transposable element derived with KRAB domain via ribosome biogenesis restriction.

Transposable elements (TEs) are indispensable for human development, with critical functions in pluripotency and embryogenesis. TE sequences also contribute to human pathologies, especially cancer, with documented activities as cis/trans transcriptional regulators, as sources of non-coding RNAs, and as mutagens that disrupt tumor suppressors. Despite this knowledge, little is known regarding the involvement of TE-derived genes (TEGs) in tumor pathogenesis. Here, systematic analyses of TEG expression across human cancer reveal a prominent role for pogo TE derived with KRAB domain (POGK). We show that POGK acts as a tumor suppressor in triple-negative breast cancer (TNBC) cells and that it couples with the co-repressor TRIM28 to directly block the transcription of ribosomal genes RPS16 and RPS29, in turn causing widespread inhibition of ribosomal biogenesis. We report that POGK undergoes deactivation by isoform switching in clinical TNBC, altogether revealing its exapted activities in tumor growth control.

Endothelial cell-released extracellular vesicles trigger pyroptosis and vascular inflammation to induce atherosclerosis through the delivery of HIF1A-AS2.

Extracellular vesicles (EVs) possess great potential in the modulation of cardiovascular diseases. Our current work intended to assay the clinical significance of endothelial cell (EC)-derived EVs in atherosclerosis (AS). Expression of HIF1A-AS2, miR-455-5p, and ESRRG in plasma from AS patients and mice and EVs from ox-LDL-treated ECs was measured. Interactions among HIF1A-AS2, miR-455-5p, ESRRG, and NLRP3 were analyzed. Next, EVs were co-cultured with ECs, and ectopic expression and depletion experimentations of HIF1A-AS2, miR-455-5p, ESRRG, and/or NLRP3 were carried out to assay their roles in pyroptosis and inflammation of ECs in AS. At last, the effects of HIF1A-AS2 shuttled by EC-derived EVs on EC pyroptosis and vascular inflammation in AS were verified in vivo. HIF1A-AS2 and ESRRG were highly expressed, while miR-455-5p was poorly expressed in AS. HIF1A-AS2 could sponge miR-455-5p to elevate the expression of ESRRG and NLRP3. Both in vitro and in vivo experiments revealed that ECs-derived EVs carrying HIF1A-AS2 induced the pyroptosis and vascular inflammation of ECs to promote the progression of AS by sponging miR-455-5p via ESRRG/NLRP3. HIF1A-AS2 shuttled by ECs-derived EVs can accelerate the progression of AS by downregulating miR-455-5p and upregulating ESRRG and NLRP3.

Development and validation of a nomogram for major adverse cardiovascular events after chronic total occlusion percutaneous coronary intervention for ischemic heart failure.

BACKGROUND: Chronic total occlusion percutaneous coronary intervention (CTO-PCI) is an available means of revascularization in patients with ischemic heart failure (IHF). However, the prognosis of IHF patients undergoing CTO-PCI remains unclear due to the lack of reliable clinical predictive tools. AIM: This study aimed to establish a nomogram for major adverse cardiovascular events (MACE) after CTO-PCI in IHF patients. METHODS: Sixty-seven potential predictive variables for MACE in 560 IHF patients undergoing CTO-PCI were screened using least absolute shrinkage and selection operator regression. A nomogram was constructed based on multivariable Cox regression to visualize the risk of MACE, and then evaluation was carried out using the concordance index (C-index), time-independent receiver operating characteristic (timeROC) curves, calibration curves, and decision curve analysis (DCA). RESULTS: During a median follow-up of 32.0 months, there were 208 MACE occurrences. Seven variables were selected for nomogram construction: age, left ventricular ejection fraction, left ventricular end-diastolic diameter, N-terminal precursor B-type diuretic peptide, bending, and use of intravascular ultrasound and beta-blockers. The C-index was 0.715 (0.680-0.750) and the internal validation result was 0.715 (0.676-0.748). The timeROC area under the curve at 6 months, 1 year, and 2 years was 0.750 (0.653-0.846), 0.747 (0.690-0.804), and 0.753 (0.708-0.798), respectively. The calibration curves and DCA showed the nomogram had acceptable calibration and clinical applicability. CONCLUSIONS: We developed a simple and efficient nomogram for MACE after CTO-PCI in IHF patients, which helps in early risk stratification and postoperative management optimization.

RGS16 regulates Hippo-YAP activity to promote esophageal cancer cell proliferation and migration.

Esophageal Squamous Cell Carcinoma (ESCC) is a common malignant tumor of digestive tract, accounting for 90% of all pathological types of esophageal cancer. Despite the rapid development of multi-disciplinary treatment such as surgery, chemotherapy, radiotherapy and chemoradiotherapy, the prognosis of patients with ESCC is still poor. Regulators of G-protein signaling (RGSs) are involved in the processes of various cancers. The expression levels of its family member RGS16 are abnormally elevated in a variety of tumors, but its role in ESCC is still unclear. We found that RGS16 expression is aberrantly increased in ESCC tissues and correlated with poor prognosis of ESCC patients from The Cancer Genome Atlas (TCGA) database and our collected ESCC tissues. Moreover, knockdown of RGS16 in two ESCC cells could indeed inhibit their proliferation and migration. We further explored the molecular mechanism of RGS16 in ESCC, and the correlation analysis from TCGA database showed that the mRNA levels of RGS16 was positively correlated with that of CTGF and CYR61, two target genes of Hippo-YAP signaling. Consistently, RGS16- knockdown significantly inhibited the expression of CTGF and CYR61 in ESCC cells. We found that the phosphorylation levels of LATS1 and YAP were significantly increased and YAP translocated into the cytoplasm after depletion of RGS16 in ESCC cells. Also, RGS16-knockdown promoted the interaction between LATS1 and upstream kinase MST1. In addition, reintroduction of a constitutive active YAP5A mutant significantly rescued CTGF expression and cell proliferation in RGS16-knockdown cells. Together, our work revealed that RGS16 promoted YAP activity through disrupting the interaction between LATS1 and MST1, thus promoting the proliferation and migration of ESCC cells.

OTUB1 alleviates NASH through inhibition of the TRAF6-ASK1 signaling pathways.

BACKGROUND AND AIMS: NAFLD is considered as the hepatic manifestation of the metabolic syndrome, which includes insulin resistance, obesity and hyperlipidemia. NASH is a progressive stage of NAFLD with severe hepatic steatosis, hepatocyte death, inflammation, and fibrosis. Currently, no pharmacological interventions specifically tailored for NASH are approved. Ovarian tumor domain, ubiquitin aldehyde binding 1 (OTUB1), the founding member of deubiquitinases, regulates many metabolism-associated signaling pathways. However, the role of OTUB1 in NASH is unclarified. METHODS AND RESULTS: We demonstrated that mice with Otub1 deficiency exhibited aggravated high-fat diet-induced and high-fat high-cholesterol (HFHC) diet-induced hyperinsulinemia and liver steatosis. Notably, hepatocyte-specific overexpression of Otub1 markedly alleviated HFHC diet-induced hepatic steatosis, inflammatory responses, and liver fibrosis. Mechanistically, we identified apoptosis signal-regulating kinase 1 (ASK1) as a key candidate target of OTUB1 through RNA-sequencing analysis and immunoblot analysis. Through immunoprecipitation-mass spectrometry analysis, we further found that OTUB1 directly bound to tumor necrosis factor receptor-associated factor 6 (TRAF6) and suppressed its lysine 63-linked polyubiquitination, thus inhibiting the activation of ASK1 and its downstream pathway. CONCLUSIONS: OTUB1 is a key suppressor of NASH that inhibits polyubiquitinations of TRAF6 and attenuated TRAF6-mediated ASK1 activation. Targeting the OTUB1-TRAF6-ASK1 axis may be a promising therapeutic strategy for NASH.

Myeloid lncRNA LOUP mediates opposing regulatory effects of RUNX1 and RUNX1-ETO in t(8;21) AML.

The mechanism underlying cell type-specific gene induction conferred by ubiquitous transcription factors as well as disruptions caused by their chimeric derivatives in leukemia is not well understood. Here, we investigate whether RNAs coordinate with transcription factors to drive myeloid gene transcription. In an integrated genome-wide approach surveying for gene loci exhibiting concurrent RNA and DNA interactions with the broadly expressed Runt-related transcription factor 1 (RUNX1), we identified the long noncoding RNA (lncRNA) originating from the upstream regulatory element of PU.1 (LOUP). This myeloid-specific and polyadenylated lncRNA induces myeloid differentiation and inhibits cell growth, acting as a transcriptional inducer of the myeloid master regulator PU.1. Mechanistically, LOUP recruits RUNX1 to both the PU.1 enhancer and the promoter, leading to the formation of an active chromatin loop. In t(8;21) acute myeloid leukemia (AML), wherein RUNX1 is fused to ETO, the resulting oncogenic fusion protein, RUNX1-ETO, limits chromatin accessibility at the LOUP locus, causing inhibition of LOUP and PU.1 expression. These findings highlight the important role of the interplay between cell-type-specific RNAs and transcription factors, as well as their oncogenic derivatives in modulating lineage-gene activation and raise the possibility that RNA regulators of transcription factors represent alternative targets for therapeutic development.

Konjac glucomannan attenuate high-fat diet-fed obesity through enhancing ß-adrenergic-mediated thermogenesis in inguinal white adipose tissue in mice.

Konjac glucomannan (KGM) has been reported to prevent high-fat diet-induced obesity, and we study investigated whether dietary supplementation with KGM can prevent obesity by increasing energy expenditure in inguinal white adipose tissue (iWAT) of high-fat diet (HF) -fed mice. Weaned mice fed the control diet (Con), HF, or HF plus KGM (8%, w/w, HFK) were divided into three groups. The results showed that 10-week supplementation with KGM significantly reduced partial adipose tissue weight and body weight, and improved glucose tolerance. Compared to the HF group, plasma lipid concentrations in the HFK group were greatly decreased to the control level. Moreover, transcriptomic research has shown that genes that are mainly associated with energy and lipid metabolism are significantly altered in iWAT. Mechanistically, KGM stimulated thermogenesis by promoting the expression of uncoupling protein-1 (UCP1) and the ß3-adrenergic receptor (ADR3ß). Taken together, our results suggest that dietary supplementation with konjac glucomannan can effectively alleviate obesity induced by a high-fat diet by activating ADR3ß-mediated iWAT thermogenesis. Dietary supplementation with KGM can effectively alleviate high fat diet- induced obesity mice by via activating ADR3ß-mediated thermogenesis of iWAT.

Lysine acetyltransferase Tip60 is required for hematopoietic stem cell maintenance.

Hematopoietic stem cells (HSCs) have the potential to replenish the blood system for the lifetime of the organism. Their 2 defining properties, self-renewal and differentiation, are tightly regulated by the epigenetic machineries. Using conditional gene-knockout models, we demonstrated a critical requirement of lysine acetyltransferase 5 (Kat5, also known as Tip60) for murine HSC maintenance in both the embryonic and adult stages, which depends on its acetyltransferase activity. Genome-wide chromatin and transcriptome profiling in murine hematopoietic stem and progenitor cells revealed that Tip60 colocalizes with c-Myc and that Tip60 deletion suppress the expression of Myc target genes, which are associated with critical biological processes for HSC maintenance, cell cycling, and DNA repair. Notably, acetylated H2A.Z (acH2A.Z) was enriched at the Tip60-bound active chromatin, and Tip60 deletion induced a robust reduction in the acH2A.Z/H2A.Z ratio. These results uncover a critical epigenetic regulatory layer for HSC maintenance, at least in part through Tip60-dependent H2A.Z acetylation to activate Myc target genes.

Different Doses of Empagliflozin in Patients with Heart Failure with Reduced Ejection Fraction.

It was unclear whether there are discrepancies among the efficacy and safety of different doses of empagliflozin in patients with heart failure with reduced ejection fraction (HFrEF). The aim of this study was to compare the efficacy and safety of 25 mg and 10 mg of empagliflozin in HFrEF patients.In this 3-month, single-center, open-label, randomized, positive-controlled, parallel-group study, 100 patients with HFrEF were divided into two groups, namely, groups A (n = 50) and B (n = 50), which were given 25 mg/day and 10 mg/day of empagliflozin, respectively. Cardiac function indexes at baseline and at the end of the third month were compared between the two groups, as well as adverse events during the 3-month follow-up period. The primary outcome of this study was the change in the left ventricular ejection fraction (LVEF), and the secondary outcomes were the change in the left ventricular end-diastolic diameter (LVEDD) and the incidences of hypotension, acute kidney injury (AKI), and genitourinary infections.At the end of the third month, the changes in the LVEF and LVEDD were greater in group A than those in group B (P < 0.05). During the 3-month follow-up period, the differences in the incidences of hypotension, AKI, and genitourinary infections between the two groups were statistically insignificant (P > 0.05).The results from this study suggested that 25 mg of empagliflozin might be better than 10 mg in improving heart function in HFrEF patients, and the safety profiles of 25 mg and 10 mg of empagliflozin are comparable. Further studies are expected to substantiate our speculations.

Runt-related transcription factor 1 (Runx1) aggravates pathological cardiac hypertrophy by promoting p53 expression.

Cardiac hypertrophy and the resultant heart failure are among the most common causes of morbidity and mortality worldwide; thus, identifying the key factor mediating pathological cardiac hypertrophy is critically important for developing the strategy to protect against heart failure. Runx1 (Runt-related transcription factor 1) acts as an essential transcription factor that functions in a variety of cellular processes including differentiation, proliferation, tissue growth and DNA damage response. However, relatively little is known about the role of Runx1 in heart, especially cardiac hypertrophy and heart failure. In the present study, we investigated the role of Runx1 in experimentally pathological cardiac hypertrophy. The in vitro model was induced by Ang II exposure to cultured neonatal rat cardiomyocytes, and the in vivo pathological cardiac hypertrophy models were induced by chronic pressure overload in mice. Runx1 expression is increased in heart tissues from mice with pressure overload-induced cardiac hypertrophy and in neonatal rat cardiomyocytes in response to Ang II stimulation. Moreover, knockdown of cardiac Runx1 alleviates the pressure overload-induced cardiac hypertrophy. Mechanistically, Runx1 activates the p53 signalling by binding to the p53 gene and promotes its transcription. Rescue experiments indicate that Runx1 promotes cardiac hypertrophy in a p53-dependent manner. Remarkably, we demonstrated that Ro5-3335 (a Runx1 inhibitor) acts as a potential therapeutic drug for treating pathological cardiac hypertrophy. In summary, we conclude that Runx1 is a novel mediator and therapeutic target for pathological cardiac hypertrophy.

Prevalence and clinical outcomes of cardiac injury in patients with COVID-19: A systematic review and meta-analysis.

BACKGROUND AND AIMS: Emerging data have linked the presence of cardiac injury with a worse prognosis in novel coronavirus disease 2019 (COVID-19) patients. However, available data cannot clearly characterize the correlation between cardiac injury and COVID-19. Thus, we conducted a meta-analysis of recent studies to 1) explore the prevalence of cardiac injury in different types of COVID-19 patients and 2) evaluate the association between cardiac injury and worse prognosis (severe disease, admission to ICU, and mortality) in patients with COVID-19. METHODS AND RESULTS: Literature search was conducted through PubMed, the Cochrane Library, Embase, and MedRxiv databases. A meta-analysis was performed with Stata 14.0. A fixed-effects model was used if the I2 values ≤ 50%, otherwise the random-effects model was performed. The prevalence of cardiac injury was 19% (95% CI: 0.15-0.22, and p < 0.001) in total COVID-19 patients, 36% (95% CI: 0.25-0.47, and p < 0.001) in severe COVID-19 patients, and 48% (95% CI: 0.30-0.66, and p < 0.001) in non-survivors. Furthermore, cardiac injury was found to be associated with a significant increase in the risk of poor outcomes with a pooled effect size (ES) of 8.46 (95% CI: 3.76-19.06, and p = 0.062), severe disease with an ES of 3.54 (95% CI: 2.25-5.58, and p < 0.001), admission to ICU with an ES of 5.03 (95% CI: 2.69-9.39, and p < 0.001), and mortality with an ES of 4.99 (95% CI: 3.38-7.37, and p < 0.001). CONCLUSIONS: The prevalence of cardiac injury was greatly increased in COVID-19 patients, particularly in patients with severe disease and non-survivors. COVID-19 patients with cardiac injury are more likely to be associated with poor outcomes, severity of disease, admission to ICU, and mortality.

miR-222 inhibits cardiac fibrosis in diabetic mice heart via regulating Wnt/ß-catenin-mediated endothelium to mesenchymal transition.

miR-222 participates in many cardiovascular diseases, but its effect on cardiac remodeling induced by diabetes is unclear. This study evaluated the functional role of miR-222 in cardiac fibrosis in diabetic mice. Streptozotocin (STZ) was used to establish a type 1 diabetic mouse model. After 10 weeks of STZ injection, mice were intravenously injected with Ad-miR-222 to induce the overexpression of miR-222. miR-222 overexpression reduced cardiac fibrosis and improved cardiac function in diabetic mice. Mechanistically, miR-222 inhibited the endothelium to mesenchymal transition (EndMT) in diabetic mouse hearts. Mouse heart fibroblasts and endothelial cells were isolated and cultured with high glucose (HG). An miR-222 mimic did not affect HG-induced fibroblast activation and function but did suppress the HG-induced EndMT process. The antagonism of miR-222 by antagomir inhibited HG-induced EndMT. miR-222 regulated the promoter region of ß-catenin, thus negatively regulating the Wnt/ß-catenin pathway, which was confirmed by ß-catenin siRNA. Taken together, our results indicated that miR-222 inhibited cardiac fibrosis in diabetic mice via negatively regulating Wnt/ß-catenin-mediated EndMT.

HLA-A*02:01 allele is associated with tanshinone-induced cutaneous drug reactions in Chinese population.

Tanshinone, a widely used Chinese patent medicine, has been confirmed to have various kinds of pharmacological effects although frequently causing cutaneous adverse drug reactions (cADRs). We aim to identify whether human leukocyte antigen (HLA) class I alleles are associated with tanshinone-induced cADRs in Han Chinese. The association study including 18 patients with tanshinone-induced cADRs, 67 tanshinone-tolerant volunteers, and two general population databases consisted of 10,689 and 169,995 healthy subjects was performed. The frequency of tanshinone-induced cADRs patients carrying HLA-A*02:01 was significantly higher when compared with the general control groups (OR = 6.25, Pc = 7.20 × 10-5; OR = 7.14, Pc = 8.00 × 10-6), and with the tolerant group (OR = 5.09, Pc = 0.024). The molecular docking assay confirmed high affinity of the ingredients of tanshinone towards HLA-A*02:01 (≤-7.5 kcal/mol). The result suggested HLA-A*02:01 may work as a promisingly predictive marker for tanshinone personalized therapy in Han Chinese.

A novel signature based on microvascular invasion predicts the recurrence of HCC.

BACKGROUND AND OBJECTIVES: In hepatocellular carcinoma (HCC) patients, microvascular invasion (MVI) is associated with worse outcomes regardless of treatment. No single reliable preoperative factor exists to predict MVI. The aim of the work described here was to develop a new MVI- based mRNA biomarker to differentiate between high and low risk patients. METHODS: Using The Cancer Genome Atlas (TCGA) database, we collected data from 315 HCC patients, including mRNA expression and complete clinical data. We generated a seven-mRNA signature to predict patient outcomes. The mRNA signature was validated using the GSE36376 cohort. Finally, we tested the formula in our own 53 HCC patients using qPCR for the seven mRNAs and analyzing the computed tomography (CT) features. RESULTS: This seven-mRNA signature significantly correlated with length of recurrence-free survival (RFS) and overall survival (OS) for both the training and validation groups. RFS and OS were briefer in high risk versus low risk patients. A Kaplan-Meier analysis also indicated that survival time was significantly shortened in the high risk group versus the low risk group. Time-dependent receiver operating characteristic analysis demonstrated good predictive performance for the seven-mRNA signature. The mRNA signature also acts as an independent factor according to a Multivariate analysis. Our results are consistent with the seven-mRNA formula risk score. CONCLUSION: Our research showed a novel seven-mRNA biomarker based on MVI predicting RFS and OS in HCC patients. This mRNA signature can stratify patients into subgroups based on their risk of recurrence to help guide individualized treatment and precision management in HCC.

Dual Specificity Phosphatase 12 Regulates Hepatic Lipid Metabolism Through Inhibition of the Lipogenesis and Apoptosis Signal-Regulating Kinase 1 Pathways.

Nonalcoholic fatty liver disease (NAFLD) has become the most common cause of chronic liver disease worldwide. Due to the growing economic burden of NAFLD on public health, it has become an emergent target for clinical intervention. DUSP12 is a member of the dual specificity phosphatase (DUSP) family, which plays important roles in brown adipocyte differentiation, microbial infection, and cardiac hypertrophy. However, the role of DUSP12 in NAFLD has yet to be clarified. Here, we reveal that DUSP12 protects against hepatic steatosis and inflammation in L02 cells after palmitic acid/oleic acid treatment. We demonstrate that hepatocyte specific DUSP12-deficient mice exhibit high-fat diet (HFD)-induced and high-fat high-cholesterol diet-induced hyperinsulinemia and liver steatosis and decreased insulin sensitivity. Consistently, DUSP12 overexpression in hepatocyte could reduce HFD-induced hepatic steatosis, insulin resistance, and inflammation. At the molecular level, steatosis in the absence of DUSP12 was characterized by elevated apoptosis signal-regulating kinase 1 (ASK1), which mediates the mitogen-activated protein kinase (MAPK) pathway and hepatic metabolism. DUSP12 physically binds to ASK1, promotes its dephosphorylation, and inhibits its action on ASK1-related proteins, JUN N-terminal kinase, and p38 MAPK in order to inhibit lipogenesis under high-fat conditions. Conclusion: DUSP12 acts as a positive regulator in hepatic steatosis and offers potential therapeutic opportunities for NAFLD.

TIP60 represses activation of endogenous retroviral elements.

TIP60 is a lysine acetyltransferase and is known to be a haplo-insufficient tumor suppressor. TIP60 downregulation is an early event in tumorigenesis which has been observed in several cancer types including breast and colorectal cancers. However, the mechanism by which it regulates tumor progression is not well understood. In this study, we identified the role of TIP60 in the silencing of endogenous retroviral elements (ERVs). TIP60-mediated silencing of ERVs is dependent on BRD4. TIP60 and BRD4 positively regulate the expression of enzymes, SUV39H1 and SETDB1 and thereby, the global H3K9 trimethylation (H3K9me3) level. In colorectal cancer, we found that the loss of TIP60 de-represses retrotransposon elements genome-wide, which in turn activate the cellular response to pathogens, mediated by STING, culminating in an induction of Interferon Regulatory Factor 7 (IRF7) and associated inflammatory response. In summary, this study has identified a unique mechanism of ERV regulation in cancer cells mediated by TIP60 and BRD4 through regulation of histone H3 K9 trimethylation, and a new tumor suppressive role of TIP60 in vivo.

The long noncoding RNA XIST regulates cardiac hypertrophy by targeting miR-101.

Cardiac hypertrophy and its resultant heart failure are among the most common causes of mortality, worldwide. Long noncoding RNAs (lncRNAs) are involved in diverse biological processes, and their vital role in the regulation of cardiac hypertrophy is increasingly being discovered. Nevertheless, the biological roles of lncRNA X-inactive specific transcript (XIST) in cardiac hypertrophy are scarcely reported, and the current study was designed to determine whether cardiac hypertrophy can be regulated by XIST and to elucidate the related mechanism. The animals were randomized to receive either an adeno-associated virus expressing XIST or control plasmid via a single bolus-tail vein injection. Two weeks later, hypertrophy was established by transverse aortic constriction (TAC) surgery. In vitro, H9c2 cells were used to explore the potential molecular mechanism of XIST in the regulation of phenylephrine (PE)-induced cardiomyocyte hypertrophy. A luciferase reporter assay and RNA immunoprecipitation were performed to explore the relationships among XIST, microRNA (miR)-101, and toll-like receptor 2 (TLR2). In this study, we demonstrated that the expression of XIST was significantly upregulated in hypertrophic mouse hearts and PE-treated cardiomyocytes. Then, we observed that knockdown of XIST attenuated PE-induced cardiomyocyte hypertrophy. Conversely, overexpression of XIST aggravated TAC-induced cardiac hypertrophy. Finally, we demonstrated that miR-101 was a direct target of XIST, whereas TLR2 was a target of miR-101. Rescue assays further confirmed that XIST promoted the progression of cardiac hypertrophy through competitively binding with miR-101 to enhance the expression of TLR2. Collectively, these in vivo and in vitro findings identify XIST as a necessary regulator of cardiac hypertrophy due to its regulation of the miR-101/TLR2 axis, suggesting that XIST might act as a therapeutic target for the treatment of cardiac hypertrophy and heart failure.

LncRNA HOTAIR functions as a competing endogenous RNA to upregulate SIRT1 by sponging miR-34a in diabetic cardiomyopathy.

The HOX transcript antisense RNA (HOTAIR) long noncoding RNA (lncRNA), a highly abundant and conserved imprinted gene, has been implicated in many essential biological processes and diseases. However, to date, the significance of HOTAIR in diabetic cardiomyopathy (DCM) has never been investigated. The current study was designed to determine whether DCM can be regulated by HOTAIR and to elucidate the related mechanism. In vivo, streptozotocin (STZ) was injected intraperitoneally to induce type 1 diabetes in mice. Cardiomyocyte specific HOTAIR overexpression was achieved using an adeno-associated virus system 12 weeks after STZ injection. In vitro, H9c2 were used to explore the potential molecular mechanism of HOTAIR in the regulation of high-glucose-induced cardiomyocyte injury. Luciferase reporter assay and RNA immunoprecipitation (RIP) were performed to explore the relationship between HOTAIR, microRNA-34a (miR-34a), and Sirtuin 1 (SIRT1). HOTAIR expression was significantly decreased in diabetic mice hearts. Knockdown of HOTAIR in high glucose-induced H9c2 resulted in increased oxidative injury, inflammation, and apoptosis in vitro. Cardiomyocyte-specific overexpression of HOTAIR improved cardiac function, decreased oxidative stress and inflammation, and attenuated myocyte death in mice treated with STZ. Mechanistically, the expression of SIRT1/forkhead box protein O1 was significantly increased in the HOTAIR-overexpressing hearts compared with the control hearts treated with STZ. Moreover, we found HOTAIR functioned as a molecular sponge of miR-34a in H9c2 and SIRT1 was identified as a target of miR-34a. Furthermore, the protective effects of HOTAIR on DCM was abolished in SIRT1 deficiency mice in vivo. HOTAIR protected against DCM via activation of the SIRT1 expression by sponging miR-34a.

TIP60 represses telomerase expression by inhibiting Sp1 binding to the TERT promoter.

HIV1-TAT interactive protein (TIP60) is a haploinsufficient tumor suppressor. However, the potential mechanisms endowing its tumor suppressor ability remain incompletely understood. It plays a vital role in virus-induced cancers where TIP60 down-regulates the expression of human papillomavirus (HPV) oncoprotein E6 which in turn destabilizes TIP60. This intrigued us to identify the role of TIP60, in the context of a viral infection, where it is targeted by oncoproteins. Through an array of molecular biology techniques such as Chromatin immunoprecipitation, expression analysis and mass spectrometry, we establish the hitherto unknown role of TIP60 in repressing the expression of the catalytic subunit of the human telomerase complex, TERT, a key driver for immortalization. TIP60 acetylates Sp1 at K639, thus inhibiting Sp1 binding to the TERT promoter. We identified that TIP60-mediated growth suppression of HPV-induced cervical cancer is mediated in part due to TERT repression through Sp1 acetylation. In summary, our study has identified a novel substrate for TIP60 catalytic activity and a unique repressive mechanism acting at the TERT promoter in virus-induced malignancies.

Aldolase promotes the development of cardiac hypertrophy by targeting AMPK signaling.

Metabolic dysfunction is a hallmark of cardiac hypertrophy and heart failure. During cardiac failure, the metabolism of cardiomyocyte switches from fatty acid oxidation to glycolysis. However, the roles of key metabolic enzymes in cardiac hypertrophy are not understood fully. Here in the present work, we identified Aldolase A (AldoA) as a core regulator of cardiac hypertrophy. The mRNA and protein levels of AldoA were significantly up-regulated in transverse aortic constriction (TAC)- and isoproterenol (ISO)-induced hypertrophic mouse hearts. Overexpression of AldoA in cardiomyocytes promoted ISO-induced cardiomyocyte hypertrophy, whereas AldoA knockdown repressed cardiomyocyte hypertrophy. In addition, adeno-associated virus 9 (AAV9)-mediated in vivo knockdown of AldoA in the hearts rescued ISO-induced decrease in cardiac ejection fraction and fractional shortening and repressed cardiac hypertrophy. Mechanism study revealed that AldoA repressed the activation of AMP-dependent protein kinase (AMPK) signaling in a liver kinase B1 (LKB1)-dependent and AMP-independent manner. Inactivation of AMPK is a core mechanism underlying AldoA-mediated promotion of ISO-induced cardiomyocyte hypertrophy. By contrast, activation of AMPK with metformin and AICAR blocked AldoA function during cardiomyocyte hypertrophy. In summary, our data support the notion that AldoA-AMPK axis is a core regulatory signaling sensing energetic status and participates in cardiac hypertrophy.